Pattern cam follower throw out mechanism for sewing machines

ABSTRACT

A single operator influenced control member is disclosed in a sewing machine together with mechanisms associated therewith for effecting in seriatim an uncoupling of the needle reciprocating drive and elevation of the needle bar, a withdrawal of the pattern cam followers out of tracking relation with the pattern cams, and the setting of a latch device for preventing return of the operator influenced member. The retrograde preventing latch device is released by the ensuing operation of the sewing machine actuating mechanism.

United States Patent 1 Bradus et al.

[ PATTERN CAM FOLLOWER THROW-OUT MECHANISM FOR SEWING MACHINES [75]Inventors: Robert Bradus, Linden; Edward A. Bruder, Roselle; FrederickRogers, Union, all of NJ.

[73] Assignee: The Singer Company, New York,

[22] Filed: May 11, 1973 [21] Appl. No.1 359,281

[52] U.S. Cl. 112/158 A, l12/221 [51] Int. Cl D05b 3/02 [58] Field ofSearch ll2/l58 R, 158 A, 158 B, ll2/l58 D, 221

[56] References Cited 8 UNITED STATES PATENTS 3,433,189 3/1969 weiSZ112/158 R llles ll2/l58 R June 28, 1974 Vigorelli ll2/l58 R Damanll2/i58 A Primary Examiner-Wemer H. Schroeder Attorney, Agent, orFirmMarshall J. Breen; Chester A. Williams, Jr.; Edward P. SchmidtABSTRACT I A single operator influenced control member is disclosed in asewing machine together with mechanisms associated therewith foreffecting in seriatim an uncoupling of the needle reciprocating driveand elevation of the needle bar, a withdrawal of the pattern camfollowers out of tracking relation with the pattern cams, and thesetting of a latch device for preventing return of the operatorinfluenced member. The retrograde preventing latch device is released bythe ensuing operation of the sewing machine actuating mechamsm.

6 Claims, 4 Drawing Figures PATTERN CAM FOLLOWER THROW-OUT MECHANISM FORSEWING MACHINES BACKGROUND OF THEINVENTION Prior cam selectingmechanisms which could be operated while the needle penetrates the workhave the disadvantage that the needle or the work fabrics may be damagedduring cam selection. It is known to prevent the possibility of suchdamage by providing means for preventing cam selection except when theneedle occupies an elevated position but this is disadvantageous in thatit imposes an additional step in the cam selection process, namely, thatof first turning the machine handwheel to position the needle up.

The known cam selecting techniques, therefore, provide for equallydisadvantageous alternatives i.e., the possibility of needle or workfabric damage on the one hand, or the imposition of additionalmanipulative steps on the other hand.

SUMMARY OF THE INVENTION tracting mechanism prior to retraction of thecam follower out of cam tracking relation. With this arrangement, theneedle is released from the endwise reciprocating mechanism and is freedfor elevation out of the work as by alifting spring prior to camfollower throwout.

DESCRIPTION OF THE DRAWINGS With the above and additional objects andadvantages in view as will hereinafter appear, this invention isillustrated in the accompanying drawings of a preferred embodiment inwhich:

FIG. 1 is a top plan view of portions of a sewing machine cam followermechanism and portions of a skip stitch mechanism associated with asewing machine needle bar together with the pattern cam followerthrow-out mechanism of this invention shown in the position which theparts occupy during-sewing when the cam follower throw-out isineffective, I

FIG. 2 is a top plan view of only a part of the mecha nism illustratedin FIG. 1 but with the pattern can throw-out mechanism in anintermediate position in which the skip stitch mechanism is operated butthe cam follower throw-out is yet uninfluenced,

FIG. 3 is a top plan view similar to that of FIG. 2 but showing thepattern cam follower in a fully effective position, and

FIG. 4 is a disassembled perspective view of portions of the mechanismillustrated in FIG. I.

Indicated at 20 in the drawings is a pattern cam follower adapted totrack the peripheral cam surface of a pattern cam 21 in the machineframe. The pattern cam follower is carried on a pivot stud 22 in themachine frame and is engaged by a shiftable transfer plate 23 urge thepattern cam follower into tracking relation with the pattern cam.

It will be understood that the needle bar driving link 24 is adapted tobe connected withia needle bar gate (not shown) so as to impart lateraljogging movements to the gate which serve to influence lateral needlemovement in the formation of zigzag stitches. Any conventional needlebar gate arrangement may be used with the pattern cam throw-outmechanism of this invention.

For throwing the pattern cam follower 20 out of tracking relation withthe pattern cam 21, a throw-out bell crank lever 30 is fulcrumed on apivot stud 31 in the machine frame and formed with one arm 32 carrying apin 33 on which is pivoted a link 34 which extends through an aperture35 in the transfer plate 23. At the opposite side of the transfer platefrom the lever 30, the link 34 is formed with a down-turned lug 36 forengaging and shifting the transfer plate. The lever 30 is formed with asecond arm 37 adapted to be engaged by an adjustable block 38 carried bya clamp screw 39 on the upper arm 40 of a bracket 41 which isoscillatable on the pivot stud 22 and biased by a spring 43counterclockwise as shown in FIGS. 1 and 4. A roller 44 on the bracketarm 40 tracks a radially sloping cam surface 45 formed on an operatorinfluenced follower unloading disc. 46 pivoted on a vertical shaft 47 inthe machine frame. The follower unloading disc is biased into an art atrest position as shown in FIG. I by a spring 48 secured on the disc by ascrew 49 and anchored to the machine frame of which a fragment isillustrated at 50 in FIG. 1

The vertical shaft 47-on which the follower or unloading disc ispivotally mounted may form a part of a pattern cam selecting mechanismof any conventional construction for transferring the pattern camfollower 20 from one to another pattern cam 21. In any event, the camfollower retracting mechanism of this invention is selectivelyindependent of the pattern cam selector means.

A follower unloading disc 46 may be formed with any suitable knurling orfinger grip 51 to facilitate grasp by a machine operator so that it maybe turned clockwise as viewed in FIG. 1 to effect the throw-out of thepattern cam follower 21.

.It will be appreciated that in the embodiment shown in the accompanyingdrawings, turning of the follower unloading disc 46 will throw out thecam follower 20 by removing the transfer plate from the pattern cam in adirection to the left as viewed in FIG. 1. A light spring 55 which issecured on the cam follower 20 and formed with opposite arms whichextend behind the transfer plate and into engagement with the pivot stud22, re-

. spectively, will bias the pattern cam follower against the transferplate and cause the cam follower to move with the plate away from thepattern cam when the follower unloading disc is turned. It is alsopointed out that the bracket 41 may be formed with a radial lug 56whichmay be used to retract any other follower out of tracking relationwith its respective pattern cam so that the mechanism of this inventionmay be used to retract a plurality of cam followers simultaneously outof cam tracking relation.

As thus far described, it will be appreciated that when the cam followeris thrown out of tracking relation with its pattern cam 21, the needlebar driving link 24 will be shifted into an extreme position away fromthe pattern cam, and in so doing, the needle bar will be shiftedlaterally into an extreme position. If, therefore, as described thusfar, the pattern cam follower is thrown out while the needle occupies aposition penetrating in work fabric, damage may occur to the needle orto the work fabric depending upon the nature of the fabrics beingstitched and the size of the needlebeing used. If a relatively heavyfabric is being stitched, the needle may be bent or broken by camfollower retraction while the needle penetrates the work. Conversely, ifa delicate fabric is being stitched, movement of the needle laterallywhile in the work may tear or distort the delicate fabric. The presentinvention, as will now be described, incorporates a feature incombination with the cam follower throw-out mechanism by which suchpossibility of damage to the needle or to the work fabrics by operationof the cam follower throwout will be obviated.

FIGS. 1 and 4 of the drawings include illustration of 25 a fragment ofthe needle bar mechanism of a sewing machine which includes a skipstitch mechanism. This skip stitch mechanism may be constructed asdisclosed in greater detail in the copending US. Pat. application No.347,983, filed Apr. 4, 1973, Docket No. 7l-A-179 by K. D' Adams and J.P. Brockman, to which reference may be had. This mechanism includes aneedle bar 60 which is provided with a separable connection with thedrive stud 61 by which the needle bar is imparted endwise reciprocatorymovements. When the connection between the needle bar and the needle bardrive stud is unlatched, the needle bar may be elevated into a raisedposition in which the needle will be lifted out of work penetratingposition by a spring 62 an- I chored on the needle bar at one extremityand anchored at the other extremity on a projecting arm 63 of a slidemember 64 which serves the purpose of actuating the latch releasemechanism for interrupting the drive between the needle bar and eachdrive stud.

More specifically, a collar 65 secured by ascrew 66 to the needle bar 60supports a pivot screw 67 on which is swingable a latch lever 68 formedwith a latch arm 69 which is shiftable selectively into or out ofengagement beneath one latch car 70 of a bifurcated needle bar embracingwhich with the other ear 71 straddles the needle bar. The bifurcatedcars 70 and 71 are integrally constructed with the drive stud 61. Thedrive stud 61 with its integral bifurcated bracket is freely slidablealong the needle bar and can be connected with the collar 65 on theneedle bar only when the latch lever 68 is swung into the closedposition shown in FIG. 4. A release lever 75 pivoted on the collar 65 isengageable with an arm 76 formed on the latch lever68 and is formed withan extension 77 engageable with the slide member 64. As shown in FIG. 4,the slide member 64 is shiftably supported on one or more pins 80carried by the machine frame which are embraced by inclined slots 81formed in the slide member so that as the slide member is elevated itwill be moved laterally toward the right as viewed in FIG. 4 and in sodoing will shift the release lever 75 causing the latch lever to turn'and uncouple the drive between the drive stud 61 and the needle barthus releasing the needle bar for elevation response to the spring 62.

A lateral tab formed on the slide member 64 overlies a platform 91formed at the extremity of a bell crank arm 92 fulcrumed on a pin 93 inthe machine frame. A depending arm 94 of the bell crank lever ispivotally interconnected at 95 with a link 96 that is connected in turnas at 97 to a lever 98 fulcrumed on a pivot stud 99 carried in a supportbracket 100 adapted to be carried in the machine frame. The lever 98 isformed with a follower nose 101 which is held into tracking relationwith the periphery of the unloading disc 46 by a spring 102. Theperiphery of the unloading disc 46 tracked by the follower nose 101includes an outwardly inclined ramp portion 103 which merges with asegment 104 of uniform diameter. As shown in FIGS. 1, 2 and 3, theinitial increment of turning movement of the unloading disc will causethe cam follower nose 101 to track the inclined ramp portion 103 of theperipheral cam track which .will turn the bell crank arm 92 upwardlycausing the slide member of the skip stitch mechanism to be elevated tounlatch the needle bar from its drive stud. The needle bar will thus beunlatched and caused to be elevated out of work penetration prior toengagement of the block 38 with the throw-out bell crank lever 30 as isclearly shown in FIG. 2. As the unloading disc 46 is turned anadditional increment in a clockwise direction from the positionillustrated in FIG. 2 to that illustrated in FIG. 3 the cam followernose 101 will track the uniform diameter section 104 of the peripherymaintaining the skip stitch mechanism unlatched while the block 38 willshift the throw-out bell crank lever 30 and cause the pattern camfollower 20 to be retracted out of tracking relation with the patterncam 21. Using the arrangement described above, therefore, the patterncam follower may be removed out of tracking relation with its patterncam at any point in the operation of the sewing machine without regardto needle or work fabric damage.

An additional feature of this invention resides in a mechanism effectiveto retain the operator influenced unloading disc 46 in the fullyeffective position maintaining the pattern cam follower thrown out oftracking relation with the pattern cam 21 so that the hands of a machineoperator are freed, for instance, to manipulate a cam selectingmechanism or other sewing machine control devices without therequirement of maintaining the unloading disc in such fully effectiveposition. Latching of the unloading disc 46 in the fully effectiveposition is influenced by a latch lever which is fulcrumed on a pivotpin lll carried in a support yoke l 12 secured beneath the supportbracket 100. Preferably, the latch lever 110 is made up of a latch arm113 which is secured by a fastening screw 114 to one arm 115 of a latchrelease bell crank lever 116 having a trip arm 117 which projects intothe path of a cam block 118 secured as by a set screw 119 to a shaft 120which is a part of the sewing machine actuating mechanism. The latch arm113 is formed with a projecting finger 121 which extends through a slot122 in the support bracket 100 into engagement with a peripheral portion123 of the unloading disc 46. A spring 124 serves to bias the latchlever 110 in a direction to maintain the latch finger 121 pressed intoengagement with the peripheral portion 123 of the unloading disc. Asshown in FIG. 3 a latch notch 125 is formed in the peripheral portion123 of the unloading disc and is adapted in the fully effective positionof the unloading disc 46 to accommodate the latch finger 121 which thenmaintains the unloading disc in such fully effective position.

When the sewing machine actuating mechanism is next operated either by ahand turning of the sewing machine mechanism or by an initiation of theoperation of the sewing machine under the conventional power drive, thecam block 118 will engage and shift the trip arm 117 and with it thelatch lever 110 to shift the latch finger 121 out of the latch notch 125thus releasing the unloading disc 46 for return by the biasing effectiveof spring 48 into the position shown in FIG. 1 in which the pattern camfollower will be reestablished in efiective tracking relation with thecam 21.

Having set forth the nature of this invention what is claimed herein is:

1. In a sewing machine having stitch forming instrumentalities,actuating mechanism for said stitch forming instrumentalities, patterninformation carrier means driven by said actuating mechanism, a followertracking said pattern information carrier means, and operativeconnections between said follower and said stitch forminginstrumentalities, a follower throw-out mechanism comprising a controlmember shiftably supported on said sewing machine for movementselectively between an ineffective extreme position through anintermediate position to an effective extreme position, separable clutchmeans arranged between said stitch forming instrumentalities and saidactuating mechanism, throw-out mechanism for said separable clutch meansoperative in said intermediate and effective extreme positions of saidcontrol member, and a follower retracting mechanism operativelyresponsive to movement of said control member into said effectiveextreme position.

2. In a sewing machine as set forth in claim 1 in which said stitchforming instrumentalities include a reciprocable work penetrating needleand said separable clutch means is arranged between said needle and theactuating mechanism for imparting work penetrating reciprocation to saidneedle, and in which biasing means is provided for urging said needleout of work penetrating position upon operation of the throw-outmechanism for said separable clutch means prior to the operation of saidfollower retracting mechanism.

3. In a sewing machine as set forth in claim 1 in which said patterninformation carrier means includes'a rotatable pattern cam and in whichsaid follower comprises a lever pivotally supportedin said sewingmachine for oscillation in response to tracking of said pattern cam inwhich said throwout mechanism for said separable clutch means becomeseffective prior to movement of said follower lever in response to saidfollower retracting mechanism.

4. In a sewing machine as set forth in claim 3 in which said patterninformation carrier means includes a plurality of rotatable pattern camsarranged coaxially in a stack, and pattern cam selector means arrangedon said sewing machine effective independently of said followerthrow-out mechanism.

5. In a sewing machine as set forth in claim 1 including latch means forretaining said control member in said effective extreme position.

6. In a sewing machine as set forth in claim 5 including spring meansbiasing said control member toward said ineffective extreme position,and latch release means carried by said sewing machine actuatingmechanism and effective upon initiation of actuation of said stitchforming instrumentalities for releasing said latch means which retainssaid control member in said effective extreme position.

1. In a sewing machine having stitch forming instrumentalities, actuating mechanism for said stitch forming instrumentalities, pattern information carrier means driven by said actuating mechanism, a follower tracking said pattern information carrier means, and operative connections between said follower and said stitch forming instrumentalities, a follower throw-out mechanism comprising a control member shiftably supported on said sewing machine for movement selectivelY between an ineffective extreme position through an intermediate position to an effective extreme position, separable clutch means arranged between said stitch forming instrumentalities and said actuating mechanism, throw-out mechanism for said separable clutch means operative in said intermediate and effective extreme positions of said control member, and a follower retracting mechanism operatively responsive to movement of said control member into said effective extreme position.
 2. In a sewing machine as set forth in claim 1 in which said stitch forming instrumentalities include a reciprocable work penetrating needle and said separable clutch means is arranged between said needle and the actuating mechanism for imparting work penetrating reciprocation to said needle, and in which biasing means is provided for urging said needle out of work penetrating position upon operation of the throw-out mechanism for said separable clutch means prior to the operation of said follower retracting mechanism.
 3. In a sewing machine as set forth in claim 1 in which said pattern information carrier means includes a rotatable pattern cam and in which said follower comprises a lever pivotally supported in said sewing machine for oscillation in response to tracking of said pattern cam in which said throwout mechanism for said separable clutch means becomes effective prior to movement of said follower lever in response to said follower retracting mechanism.
 4. In a sewing machine as set forth in claim 3 in which said pattern information carrier means includes a plurality of rotatable pattern cams arranged coaxially in a stack, and pattern cam selector means arranged on said sewing machine effective independently of said follower throw-out mechanism.
 5. In a sewing machine as set forth in claim 1 including latch means for retaining said control member in said effective extreme position.
 6. In a sewing machine as set forth in claim 5 including spring means biasing said control member toward said ineffective extreme position, and latch release means carried by said sewing machine actuating mechanism and effective upon initiation of actuation of said stitch forming instrumentalities for releasing said latch means which retains said control member in said effective extreme position. 